Time Travel is impossible

Well... Not impossible, just not survivable.

We've all seen the movies, you get into the time machine,
go back a few hundred years and pop up in a field or summat.

Think about it: if you had a time machine and could go back just an hour where would you be?

Remember, you are just going back in time and not space, so you'll end up in the same place in space.
Do you think you'll just end up still where you were an hour ago?

You know the earth is rotating about it's axis, right?
See where I'm going with this one already?

So the earth rotated by 1/24th of a turn so you'll end up in somewhere else west of where you are now since the earth moved!

But it's worse than that:

The earth is also rotating around the sun, so it will have moved further in its orbit won't it. You'll end up appearing either above ground or embedded in it!

There's more:

Don't forget the solar system is in the Milky Way, a spiral galaxy which is rotating.
So the whole solar system will have moved relative to the galactic centre so you will actually end up space somewhere near the earth where the solar system was!

Not finished yet.

The Milky Way is moving out as part of the universal expansion from some central point in the universe.
So you may end up in some other place in the galaxy or even in intergalactic space!

The reality is no-one knows for sure how the universe is expanding, or in which absolute direction our galaxy is moving relative to some absolute point in space.

So after just one hour you could be anywhere, but you certainly will not be exactly here on earth but just one hour in the past.
The earth wasn't here one hour ago!

So where would the earth be a hundred years from now?
No-one knows.

So if you travel into the past (or future) chances are you'll be in the vacuum of space.
...and dead pretty soon!